Advanced Materials for Micro- and Nano-Systems Programme, Singapore-MIT Alliance, National University of Singapore, Singapore 117576, Singapore.
Langmuir. 2012 Jul 31;28(30):11048-55. doi: 10.1021/la301956q. Epub 2012 Jul 16.
Wetting is a pervasive phenomenon that governs many natural and artificial processes. Asymmetric wetting along a single axis, in particular, has generated considerable interest but has thus far been achieved only by the creation of structural anisotropy. In this paper, we report that such directional wetting can also be achieved by anisotropically coating nanostructure surfaces with materials that modify the nanostructure surface energy, a phenomenon that has not been observed in natural or artificial systems thus far. Moreover, by combining this newfound chemical influence on wetting with topographic features, we are able to restrict wetting in one, two and three directions. A model that explains these findings in terms of anisotropy of the pinning forces at the triple phase contact line is presented. Through the resulting insights, a flexible method for precise control of wetting is created.
润湿是一种普遍存在的现象，控制着许多自然和人为过程。特别是，沿着单一轴的不对称润湿引起了相当大的兴趣，但迄今为止，这种润湿只能通过创建结构各向异性来实现。在本文中，我们报告说，通过各向异性地涂覆具有改变纳米结构表面能的材料，也可以在纳米结构表面上实现这种定向润湿，这是迄今为止在自然或人工系统中尚未观察到的现象。此外，通过将这种新发现的对润湿的化学影响与地形特征相结合，我们能够将润湿限制在一个、两个和三个方向上。提出了一个模型，根据三相接触线处的钉扎力各向异性来解释这些发现。通过由此产生的见解，创建了一种用于精确控制润湿的灵活方法。
